Percutaneous Screw Fixation Promotes Healing of Lateral Condyle Nonunion in Children Dominique M. Knight, FRCS(Tr&Orth), MBBS, MRCS, BSc, Cristina Alves, MD, FEBOT, Benjamin Alman, MD, FRCSC, and Andrew Howard, MD, MSC, FRCSC Background: This retrospective study examined whether pedia- tric lateral condyle nonunions could be successfully managed by percutaneous screw fixation. We report the outcome of this minimally invasive technique avoiding open reduction and bone grafting associated with the risk of avascular necrosis (AVN), infection, and stiffness. Methods: The hospital radiology database was searched between 1998 and 2008. This identified 16 consecutive patients aged 2 to 10 years, with lateral condyle nonunions treated with percutaneous screw fixation. We assessed clinical and radiographic outcomes from presentation to final follow-up. Potential risk factors for recalcitrant nonunion were identified. Categorical variables are presented as proportions and percentages. Continuous variables were assessed for normality with the d’Agostino-Pearson test. Normally dis- tributed variables are presented as means with 1 SD. Non-normally distributed data are presented as medians with interquartile range. Results: Outcome was defined as successful if radiologic and clinical union was achieved. Twelve patients (75%) united after surgery, at a mean of 16.2 weeks (± 6.74). Four (25%) failed to unite. The failures presented with nonunion later (median of 225.5 wk from initial injury). This was significantly different (P = 0.039) from presentation in the successful group (median time 15.7 wk). Median age at injury was 5.1 years (range, 3.2 to 7.2) in the successful and 2.8 years (range, 2.1 to 4.7) in the unsuccessful group (P = 0.18). Overall, mean time from non- union diagnosis to percutaneous surgery was 5.2 weeks (± 4.11). Forty-four percent had implant removal once union was ach- ieved and no cases of AVN were reported. Conclusions: We demonstrate this technique to be successful in nonunions addressed within 16 weeks from initial injury to di- agnosis. Our 4 failures occurred in nonunions diagnosed >31 weeks from the injury (31, 68, 383, 427 wk). All had been managed nonoperatively as their primary treatment plan. Per- cutaneous fixation is feasible and safe. Patients not achieving union were diagnosed after a greater delay. There was a trend toward successfully treated patients being younger. There were no cases of AVN, infection, or elbow stiffness. Level of Evidence: Level 4. Key Words: lateral condyle, nonunion, percutaneous fixation (J Pediatr Orthop 2014;34:155–160) F ractures of the lateral condyle account for approximately 12% of elbow fractures in the pediatric population. 1 Although the initial management of these injuries is diverse, the amount of initial displacement is an important factor in therapeutic decision-making. It is known that <1% of pa- tients managed operatively will develop a malunion, delayed union, or nonunion. 2 Most authors recommend open re- duction and internal fixation, with or without supplementary bone graft, for the treatment of lateral condyle nonunions. 3–9 This approach is associated with risks, the most important being avascular necrosis (AVN) due to the disruption of the lateral condyle’s tenuous blood supply, which enters the posterior aspect. 10 Further, opening the elbow joint and performing extensive dissection of the nonunion can lead to joint stiffness or infection. The additional exposure may not facilitate optimal reconstruction of the elbow, as the lateral condyle fragment has often hypertrophied and may not fit anatomically, contributing to the prominence often present after healing. We hypothesized that percutaneous screw fixation can be used to successfully treat lateral condyle nonunion in children. Our technique consists of a minimally invasive percutaneous screw fixation performed under fluoroscopic guidance. The elbow joint is not opened nor is there any dissection, decreasing the risk of complications observed with open surgery, namely AVN and infection. The frac- ture site is stabilized and compressed. As there is no soft tissue stripping, disturbance to any preexisting callus, or any attempt to insert bone graft, the risk of AVN is minimal. Furthermore, compression decreases the amount of joint fluid passing across the intra-articular nonunion. As the metaphyseal fragment is often larger than at the time of initial injury, larger screws can be used. 6,11 The purpose of this study was to determine the effectiveness (healing rate) and safety (complications) of percutaneous screw fixation of lateral condyle non- unions. To our knowledge, this is the first report in the literature describing this percutaneous screw fixation technique and its results in the treatment of lateral condyle nonunions in children. From the Division of Orthopaedic Surgery, The Hospital for Sick Children, Toronto, ON, Canada. The authors declare no conflict of interest. Reprints: Dominique M. Knight, FRCS(Tr&Orth), MBBS, MRCS, BSc, Bristol Royal Hospital for Children, Paul O’Gorman Building, Upper Maudlin Street, Bristol, UK BS2 8BJ. E-mail: dmaknight@ rcsed.ac.uk. Copyright r 2013 by Lippincott Williams & Wilkins ORIGINAL ARTICLE J Pediatr Orthop  Volume 34, Number 2, March 2014 www.pedorthopaedics.com | 155